known that a current of 1 A at a voltage in the electric network 1 provides power to 1 watt.But this ratio can be used to determine a power at constant potential difference and amperage.Iein determining power (P) in a DC network.For that use one of the following formulas, depending on the parameters defined in the problem: P = I * U, P = I² * R, where I - DC value, U - voltage, R - resistance.
However, most often required to determine the power of an alternating electric field in the sinusoidal current circuits.At the same time for the full power circuit taking the product of the current and voltage, taking into account the phase shift between these values, ie,active and reactive power components and the power factor.
Find the active power of the alternating
field.For this purpose, in addition to a current value necessary to know the resistance (R) of the circuit concerned.Substitute the given values in the formula Ra = I² * R and calculate the value.If the circuit has several of its parts (resistors), active power determine for each of them.Fold found the active power of the whole chain.
Calculate reactive power AC circuits.It describes the processes around the conversion of energy in the fields of inductors and capacitors.Moreover, the reactive power of active-inductive load element is a positive value and, conversely, negative - when active-capacitive load.This means that the presence in the chain of inductors its reactive power has a positive sign and the output capacitance of the capacitor - negative.To calculate the reactive power of the inductance element (Rl) or condenser (Pc) using the same formula P = I² * R, where R - Resistance particular element.Sequentially calculate the power for each element.Determine the total reactive power circuit.Add up the values found, this takes into account the sign of the reactive power of the capacitor: Pp = Rl1 + RL2 - Pc.
Determine the full power of the AC circuit.It is associated with active and reactive power the following relationship: S = √ (+ Ra² Rr²).Substitute into the formula found power values and calculate the final result.
Tip 2: How to calculate the power
Imagine this situation: you bought a new hard drive or video card, plug in and turn on the computer.A computer does not turn on.This may be influenced by several factors, one of which - the lack of power supply unit (PSU).He just did not pull a new video card and does not allow to include a PC, so as not to burn yourself.A problem that has not been designed capacity.
The fact is that modern power supply the sensor output, which will not let you turn on the PC, if the power supply can not cope with the load capacity.But BP may burn if the power consumed by the load, there will be many more of that power, which is designed PD.To avoid such incidents did not happen, expect power load and compares it with the power which stands PD.
power - it is a physical quantity that characterizes the object is given or received energy per unit time.Sometimes the power emitted (output) and absorbed (input).Like energy, power can be of different types: mechanical, acoustic, thermal, electrical, electromagnetic and so on.
from the same course of physics we know that the power P (W) for the circuit with constant current is directly proportional to the value of the voltage U (B), and a current I (A) on a chain site: P= I * U.This formula can be used not only to calculate the power consumption of the device, but also to calculate the output power supply unit and to calculate the heat output.
thermal power (heat) that stands on one of the elements of the power supply circuit will also be directly proportional to the force transmitted through all current users.I think it is not necessary to explain why the total capacity of all the elements of the computer must not exceed the maximum power output of the PSU.
I would also like to note that the system of uneven power consumption.Peaks power system typically experiences when the PC or some separate device including actuators, increasing the computational load, and so on.For devices featuring a large energy consumption, manufacturers usually specify the value of the peak power.
So that we did not burn down the power supply should be at least roughly estimate the maximum power consumption of the load, add the values of all devices currently connected to the power supply and to compare the result with the maximum powerBP itself.A total power of the devices is determined by the formula: P = p (1) + p (2) + p (3) + ... + p (i).
- how to calculate the power supply wattage